This invention relates to the provision of rotating baffle means for air movement control in a circular deep pile fabric knitting machine. It has particular usefulness when applied to circular knitting machines of the type having a rotating needle cylinder. Such machines are used for making deep pile textiles by incorporation of additional fibers in the stitches as the yarn is knitted. Prior to the formation of a stitch, each of a number of needle hooks rises into carded fiber on the surface of a respective doffer roll, engaging and drawing down a tuft of fiber which is to be incorporated into the stitch. An air jet blows over each needle as the stitch is being formed to aid in orienting the fiber taken by the needle and causing the ends of the fibers to stream toward the center of the machine.
In this process, a certain proportion of the fiber inevitably comes adrift from the surface of the doffer roll, from the needle hook, and from the stitch as it is being formed. Such stray fiber is an expensive nuisance, both in its original cost, and in the costs which are incurred in subsequently removing it from places where it is not wanted.
An exhaust system is provided, with an intake hood or bell located above the machine, and it serves to remove a considerable part of the stray fiber from the knitting area. The U.S. patent to A. J. Beucus, et al., U.S. Pat. No. 3,295,337 is illustrative of efforts which have been made to improve stray fiber control. Nevertheless, the action of the air jets directed toward the center of the machine has the result of blowing substantial amounts of stray fiber into the knitted tube as it is formed. Furthermore, the air jet associated with one stitch-forming position may disturb the air-flow patterns at one or more other stitch-forming positions in a way adversely affecting the uniformity with which fiber is held by needles in the latter positions. Most of this stray fiber become lightly frictionally engaged by the pile of the fabric, and moves down with the fabric as the knitting operation proceeds, requiring costly removal at later stages in the manufacturing process. In prior art machines, where a hole detector ring is used for a stop motion system, it has been supported from a yoke across the top of the machine, or from a spider in the bell of the exhaust hood. In either case, the support structure presents surfaces which catch and accumulate stray fiber. When bunches of fiber so collected come loose and get into the mechanism, contamination of the product and damage to the machine due to jamming may result.